ELECTROCHEMICAL CELL FOR A BATTERY COMPRISING A FIRST ELECTROCHEMICAL SUBASSEMBLY AND A SECOND CAPACITOR SUBASSEMBLY

Abstract

The invention relates to an electrochemical cell for a battery of an electric or hybrid motor vehicle, said negative electrode comprising a negative current collector comprising at least one negative foil, said positive electrode comprising a positive current collector comprising at least one positive foil, said electrochemical cell comprising at least one separator, the separator being positioned between the negative foil and the positive foil, said electrochemical cell comprising a plurality of layers of active material soaked in electrolyte, characterized in that said electrochemical cell comprises a first subassembly (100) in which the negative foil and the positive foil each comprise one of the electrolyte layers, the electrolyte layer being in contact with said separator,said electrochemical cell comprising a second sub-assembly (200) in which the negative and positive foils are in contact with the separators, said second sub-assembly (200) forming a capacitor. Figure 1,

Description

Title of the invention: Electrochemical cell for a battery comprising a first electrochemical subassembly and a second capacitor subassembly

[0001] The invention relates to electrochemical battery cells and to batteries for electric or hybrid motor vehicles.

[0002] Prior art patent application WO2022100279 is known, describing a battery cell comprising a composite current collector including a current collector body, a first protective layer, and a first heating layer. The length of the protective layer is greater than the length of the current collector body. The first protective layer is in contact with the current collector body. The first protective layer comprises a protective body and an active material. Furthermore, said first heating layer is in contact with said current collector body. The first heating layer heats said composite current collector by Joule heating. The first protective layer and the first heating layer are positioned on a single layer located on one of the surfaces of the composite current collector. However, a drawback remains.The battery cell does not contain a capacitor. Thus, when an electric current is applied, it does indeed preheat the battery cell by Joule effect, but it also passes through the active material, which is thereby impacted.

[0003] The objective of the present invention is to remedy these drawbacks and to allow uniform and rapid preheating of the electrochemical cells of a battery before recharging.

[0004] To achieve this objective, the invention proposes an electrochemical cell for a battery of an electric or hybrid motor vehicle, said electrochemical cell comprising a negative electrode and a positive electrode, said negative electrode comprising a negative current collector comprising at least one negative foil, said positive electrode comprising a positive current collector comprising at least one positive foil, said electrochemical cell comprising at least one separator, the separator being positioned between the negative foil and the positive foil, said electrochemical cell comprising a plurality of layers of active material soaked in electrolyte, notable in that said electrochemical cell comprises a first sub-assembly in which the negative foil and the positive foil each comprise one of the layers of active material, the active material layer being in contact with said separator, said electrochemical cell comprising a second sub-assembly in which the negative sheet and the positive sheet are in contact with said separator, said second sub-assembly forming a capacitor.

[0005] Thanks to the invention, it is possible to preheat the electrochemical cells of a battery uniformly and quickly.

[0006] Advantageously, said electrochemical cell having a cylindrical, prismatic or pocket shape.

[0007] Advantageously, said negative electrode and said positive electrode have a stacked configuration suitable for pocket and prismatic cells.

[0008] Alternatively, said negative electrode and said positive electrode have a wound configuration adapted to cylindrical and prismatic cells.

[0009] Preferably, said second subset is positioned at the center of the first subset.

[0010] Thus, the heat is directed from the center to the periphery of the electrochemical cell, in a uniform manner.

[0011] The invention also relates to a battery for an electric or hybrid motor vehicle, said battery comprising a plurality of electrochemical cells as previously described.

[0012] Furthermore, the invention relates to an electric or hybrid motor vehicle comprising a battery as previously described and a battery management system, said battery management system having a control current, said battery management system having a predetermined cutoff frequency, notable in that said battery management system is configured to control a sinusoidal electric current having a frequency higher than said predetermined cutoff frequency to preheat said battery, said sinusoidal current being superimposed on the control current, said second subset being configured to filter frequencies higher than said predetermined cutoff frequency.

[0013] Thus, it is possible to quickly preheat the battery before recharging it so that recharging is faster.

[0014] Furthermore, the invention relates to a method for preheating the electrochemical cells of a battery of an electric or hybrid motor vehicle, remarkable in that said method comprises a step of emitting said sinusoidal current having a frequency higher than the predetermined cut-off frequency, said sinusoidal current being controlled by said battery management system and absorbed by said second sub-assembly so as to preheat by Joule effect the electrochemical cells of said battery.

[0015] Preferably, said vehicle includes a means for controlling the battery preheating and / or a geolocation system, the battery including a temperature sensor, said emission step is implemented when said driver activates said control means or when said geolocation system detects an imminent stop at a charging station and when the battery temperature is below a predetermined threshold temperature.

[0016] Thus, the battery can be preheated before the charging process begins.

[0017] Preferably, said vehicle includes a means for detecting the connection of said vehicle to a charging station, the battery including a temperature sensor, said emission step being implemented when the connection of the vehicle to the charging station is detected by said detection means and when the temperature of the battery is below a predetermined threshold temperature.

[0018] Thus, it is possible to preheat the battery at the beginning of the charging process.

[0019] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates an electrochemical cell having a stacked configuration according to a first embodiment of the invention; - [Fig.2] schematically illustrates a detailed view of the cell electrochemical illustrated in [Fig.l]; - [Fig.3] schematically illustrates an electrochemical cell exhibiting a wound configuration according to a second embodiment of the invention.

[0020] An electrochemical cell for a battery of an electric or hybrid motor vehicle, according to a first embodiment, is schematically illustrated in [Fig. 1] and [Fig. 2]. To enable ultra-fast charging of the battery, it is necessary to be able to precondition it by preheating it. This prepares the battery and thus reduces the time required for its charging. To prepare the battery, it is necessary to heat the electrochemical cells composing it uniformly and rapidly. The preheating can be initiated before or during the charging process. Preferably, the electrochemical cell has a pocket shape as illustrated in [Fig. 1]. In another embodiment, the electrochemical cell has a prismatic or cylindrical shape. The electrochemical cell comprises a negative electrode and a positive electrode.In [Fig. 1], the negative and positive electrodes are in a stacked configuration. This stacked configuration is more suitable for electrochemical cells exhibiting [the following characteristics]. a pocket-shaped or cylindrical form. Alternatively, the negative and positive electrodes may have a wound configuration as shown in [Fig. 3]. The wound configuration is better suited for electrochemical cells with a cylindrical or prismatic shape. The negative electrode has a negative current collector 1. The positive electrode has a positive current collector 2. The negative current collector 1 and the positive current collector 2 each have a plurality of negative and positive leaves, respectively. In the wound configuration shown in [Fig. 3], the negative current collector 1 has a single negative leaf and the positive current collector 2 has a single positive leaf.The plurality of negative and positive sheets are each divided into two subgroups, namely a first part and a second part. The negative and positive sheets alternate. The electrochemical cell comprises a plurality of separators 3. Alternatively, in the coiled configuration shown in [Fig. 3], the electrochemical cell comprises a single separator 3. Each separator 3 is positioned between one of the negative and one of the positive sheets. The electrochemical cell comprises a plurality of layers of active material 4 soaked in electrolyte. The active material 4 is a layer of electrochemically active material having pores into which the electrolyte, in liquid form, penetrates.When in contact with a conductive support, the active material 4 and the electrolyte participate in charging and discharging reactions by storing and releasing ions. The active material 4 can be positive or negative. The negative active material 4 is located on the negative electrode. During discharge, the negative active material 4 releases charges. The positive active material 4 is located on the positive electrode. During discharge, the positive active material accepts charges from the negative electrode. The electrochemical cell comprises a first subassembly 100 in which each sheet, positive and negative, has one of the layers of active material 4. In this case, the conductive support is one of the positive or negative sheets of the first subassembly 100.In the first subset 100, each layer of active material 4 is in contact with one of the separators 3 and one of the positive or negative sheets. Furthermore, the electrochemical cell comprises a second subset 200 in which each negative sheet and each positive sheet is in direct contact with one of the separators 3. The second subset 200 is devoid of active material 4. In this way, the second subset 200 forms a capacitor.

[0021] Figure 3 illustrates a second embodiment in which the electrochemical cell has the wound configuration. The negative current collector 1 The cell comprises a negative plate, and the positive current collector 2 comprises a single positive plate. Furthermore, the electrochemical cell has a single separator 3. The second subassembly 200 is positioned at the center of the first subassembly 100 of the electrochemical cell. This results in more uniform heating of the electrochemical cell. However, as with the stacked configuration shown in [Fig. 1], the second subassembly 200 can be positioned anywhere else within the electrochemical cell.

[0022] Furthermore, the invention relates to a battery for an electric or hybrid motor vehicle comprising a plurality of electrochemical cells as previously described. The invention also relates to an electric or hybrid motor vehicle comprising such a battery. In addition, said vehicle comprises a battery management system, or BMS. The battery management system has a control current and a predetermined cutoff frequency. The cutoff frequency is the frequency at which the subassembly 200 begins to attenuate higher frequencies. Frequencies below this frequency are not attenuated. The control current is the electric current flowing through said battery at a given time t to ensure the operation of said battery. The control current may be zero or non-zero.The battery management system is configured to generate a sinusoidal current at a frequency higher than the predetermined cutoff frequency. This sinusoidal current is also known as alternating current. The sinusoidal current is superimposed on the control current and then absorbed exclusively by the second sub-assembly 200, which, acting as a capacitor, is configured to filter frequencies higher than the cutoff frequency in the manner of a low-pass filter. The lower frequencies, i.e., those below the cutoff frequency, allow the battery to be charged or discharged. In this way, the sinusoidal current does not affect the first sub-assembly 100 of the electrochemical cell, and consequently, it does not affect the active material 4, which is thus preserved.When the sinusoidal current, superimposed on the control current, flows through the second sub-assembly 200, the positive current collector 2 and the negative current collector 1 then act as heating resistors, allowing the temperature of the electrochemical cell to increase by Joule heating. The Joule effect is the phenomenon by which electrical energy is transformed into heat when an electric current flows through a conductor, due to the conductor's resistance. Thus, the temperature of the electrochemical cell increases uniformly. The invention therefore also relates to a method for preheating the battery of said vehicle, comprising a step of emitting said sinusoidal current controlled by said battery management system, said sinusoidal current being superimposed on the control current. a control means to generate an overall current. A portion of the overall current has a frequency higher than the predetermined cutoff frequency. The overall current is then absorbed by the second sub-assembly 200 because, as previously mentioned, the second sub-assembly 200 acts as a capacitor. Preferably, the vehicle includes a means for controlling the battery preheating. The battery includes a temperature sensor. The transmission step is implemented when the driver activates the control means and when the battery temperature is below a predetermined threshold temperature. For example, the control means is a control button that can be activated from inside the vehicle. Optionally, the vehicle includes a geolocation system.The emission step is implemented when the geolocation system detects an imminent stop at a charging station and when the battery temperature is below the predetermined threshold temperature. Alternatively, the vehicle includes a means for detecting when the vehicle is connected to a charging station, and the battery includes a temperature sensor. The emission step is implemented when the connection of the vehicle to the charging station is detected by the detection means and when the battery temperature is below the predetermined threshold temperature.

Claims

Demands

1. Electrochemical cell for a battery of an electric or hybrid motor vehicle, said electrochemical cell comprising a negative electrode and a positive electrode, said negative electrode comprising a negative current collector (1) comprising at least one negative foil, said positive electrode comprising a positive current collector (2) comprising at least one positive foil, said electrochemical cell comprising at least one separator (3), the separator (3) being positioned between the negative foil and the positive foil, said electrochemical cell comprising a plurality of layers of active material (4) soaked in electrolyte, characterized in that said electrochemical cell comprises a first subassembly (100) in which the negative foil and the positive foil each comprise one of the layers of active material (4), the layer of active material (4) being in contact with said separator (3),said electrochemical cell comprising a second sub-assembly (200) in which the negative foil and the positive foil are in contact with said separator (3), said second sub-assembly (200) forming a capacitor.

2. Electrochemical cell according to claim 1 characterized in that said electrochemical cell having a cylindrical, prismatic or pocket shape.

3. Electrochemical cell according to claim 1 or 2 characterized in that said negative electrode and said positive electrode have a stacked configuration.

4. Electrochemical cell according to claim 1 or 2 characterized in that said negative electrode and said positive electrode have a wound configuration.

5. Electrochemical cell according to claim 4 characterized in that said second sub-assembly (200) is positioned at the center of the first sub-assembly (100).

6. Battery of an electric or hybrid motor vehicle, said battery comprising a plurality of electrochemical cells according to any one of claims 1 to 5.

7. An electric or hybrid motor vehicle comprising a battery according to claim 6 and a battery management system, said battery management system having a control current, said battery management system having a predetermined cutoff frequency, characterized in that said battery management system is configured to command a sinusoidal electric current having a frequency higher than said predetermined cutoff frequency to preheat said battery, said sinusoidal current being superimposed on the control current, said second sub-assembly (200) being configured to filter frequencies higher than said predetermined cutoff frequency.

8. Method for preheating the electrochemical cells of a battery of an electric or hybrid motor vehicle according to claim 7, characterized in that said method comprises a step of emitting said sinusoidal current having a frequency higher than the predetermined cutoff frequency, said sinusoidal current being controlled by said battery management system and absorbed by said second subassembly (200) so as to preheat the electrochemical cells of said battery.

9. Method according to claim 8 characterized in that said vehicle comprises a means for controlling the preheating of the battery and / or a geolocation system, the battery comprising a temperature sensor, said emission step is implemented when said driver activates said control means or when said geolocation system detects an imminent stop at a charging station and when the battery temperature is below a predetermined threshold temperature.

10. The method according to claim 8 characterized in that said vehicle comprises a means for detecting the connection of said vehicle to a charging station, the battery comprising a temperature sensor, said emission step being implemented when the connection of the vehicle to the charging station is detected by said detection means and when the temperature of the battery is below a predetermined threshold temperature.

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